1. Field of the Invention
The present invention relates to a device for arraying a thermal printer head for use in a thermal printer, and more particularly, to a thermal printer head arraying device for use in a thermal printer which is incorporated in a cash register, in which the overall surface of a thermal printer head uniformly contacts the overall surface of a transfer roller to thereby have the thermal printer head smoothly perform a printing work, to relatively reduce the number of components in comparison with the conventional art to save a production cost, and to make the size of the product compact through a simplified structure and an assembly process simplified.
2. Description of the Related Art
As is well known, devices which can issue receipts such as an electronic cash register (ECR), a POS terminal, and a credit card terminal are widely used in convenience stores, supermarkets, restaurants, and department stores, in order to perform functions such as details of transactions, calculation of sales amount, issuance of receipts.
The cash register is a very useful device for managing sales and inventory, which processes various kinds of data accompanied by sales of products, and informs a user of the processed result, to thereby help the user to smoothly manage information.
The cash register is generally incorporated as a set including a printer, a keyboard, a display, a cash drawer, etc. However, according to enlargement and specialization of stores, owners of the stores need management of products, customers, and employees through systemization and network. Thus, demand of POS systems increases gradually.
In addition, peripheral devices which are used in the cash register and the POS system become modular. a small-sized printer which can be incorporated in a set such as a cash register, a POS terminal, and a credit card terminal as a peripheral device, is used as a device for printing a receipt which is issued from the set.
The small-sized printer is classified into a dot printer and a thermal printer according to a printing type. The dot printer can print a receipt containing details of transactions on a sheet of paper in which an impact is applied to a circulating ribbon. The thermal printer can print a receipt containing details of transactions on a sheet of paper using a thermal heat. The thermal printer having almost little noise or vibration is recently widely used.
FIG. 1 is a front view showing an example of a conventional thermal printer for use in a conventional cash register, and FIG. 2 is a side view showing an example of a conventional thermal printer for use in a conventional cash register.
As shown in FIGS. 1 and 2, a conventional thermal printer used in a conventional cash register includes a frame 100 having a predetermined internal space, a transfer roller 120 which is combined with transfer roller mounting holes (not shown) which are formed in both sides of the frame 100, and is rotatably installed to transfer a sheet of paper 110, a guider 130 for guiding the sheet of paper 110, a thermal printer head 140 which performs printing on the sheet of paper 100, a driving motor 150 which provides the transfer roller 120 with a rotational force to make the transfer roller 120 rotate, a speed reduction gear 210 which is installed between the transfer roller 120 and the driving motor 150 and reduces the rotational force of the driving motor 150 to then transfer the reduced rotational force to the transfer roller 120, a shaft 160 which is coupled with shaft mounting holes which are formed in both sides of the frame 100, a first bracket 170 to the upper side of which the thermal printer head 140 is fixed and with the lower side of which the shaft 160 is rotatably fitted, a second bracket 180 which is rotatably coupled with the shaft 160 and maintains a predetermined gap from the first bracket 170, a spring 190 which is interposed between the first and second brackets 170 and 180, and a head open lever 200 which rotates the first and second brackets 170 and 180 to isolate the thermal printer head 140 from the transfer roller 120 by a predetermined distance.
In the case of the conventional thermal printer as shown in FIGS. 1 and 2, the thermal printer head 140 should be isolated from the transfer roller 120 in order to repair the thermal printer or insert sheets of paper 110, at the state where the thermal printer head 140 contacts the transfer roller 120. In this case, when the head open lever 200 is turned in a predetermined direction, for example, clockwise, the second bracket 180 which has been supported by the head open lever 200 is elastically turned by the spring 190 around the shaft 160.
Simultaneously, the first bracket 170 to which the thermal printer head 140 is fixed is turned around the shaft 160, and thus the thermal printer head 140 is isolated from the transfer roller 120.
Meanwhile, in the case that the isolated thermal printer head 140 is made to contact the transfer roller 120 after having completed internal repair or exchange of sheets of paper at the state where the thermal printer head 140 has been isolated from the transfer roller 120, the above-described operation should be performed in reverse sequence. That is, if the head open lever 200 is turned counterclockwise, the second bracket 180 is a little turned clockwise around the shaft 160 by the eccentric rotation of the head open lever 200.
The spring 190 is pressurized by rotation of the second bracket 180. In this case, the first bracket 170 is a little turned elastically clockwise by pressurizing the spring 190.
Accordingly, the thermal printer head 140 which is fixedly installed in the upper side of the first bracket 170 narrows the gap isolated from the transfer roller 120 and contacts the transfer roller 120 elastically. As a result, a sheet of paper 110 which is placed between the transfer roller 120 and the thermal printer head 140 is smoothly transferred by the transfer roller 120. Simultaneously, the thermal printer head 140 performs printing on the sheet of paper 110.
However, in the case of the above-described conventional thermal printer, it is very difficult to accurately mount the shaft 160 and the transfer roller 120 in equilibrium. Accordingly, the overall surface of the thermal printer head 140 does not contact the overall surface of the transfer roller 120 uniformly at the process of making the thermal printer head 140 contact the transfer roller 120. That is, one side of the thermal printer head 140 contacts the transfer roller 120 and the other side thereof comes off the transfer roller 120. As a result, printing is not smoothly performed.
In addition, an operational structure of the head open lever 200 for isolating the thermal printer head 140 from the transfer roller 120 by a predetermined distance is complicated somewhat. Accordingly, the number of components becomes large and thus the number of assembly processes increases. This is one of factors which prevent a product from being compact.